title: Meta-analysis: fact or fiction? How to interpret meta-analyses.
abstract: OBJECTIVE
  Widespread use of increasingly complex statistical methods makes it ever more challenging to adequately assess the results reported and conclusions drawn in meta-analytic research. This paper aims to identify potential fallacies by in-depth examination of recent publications on mood disorders.
  
  
  METHODS
  Three meta-analyses were selected based on availability of data and representativeness of methods employed. By means of detailed re-analysis, several widespread methodological problems were identified, and the example data were used to illustrate and discuss them.
  
  
  RESULTS
  General points addressed include clear formulation of the research question, choice of effect size measures, and general choice of model. Data quality problems like missing data and publication bias are discussed along with methods to deal with them. Furthermore, aspects of meta-analytic modelling like the use of fixed or random effects, data aggregation, as well as the use of subgroups are explained, and issues of excessive complexity and data dredging pointed out. Finally, the benefit of diagnostic tools like confidence bands and the importance of transparency regarding data and methodology for the interpretation of meta-analytic results are highlighted.
  
  
  CONCLUSIONS
  Practically relevant quality criteria for readers to bear in mind when dealing with meta-analytic publications are summarized in a ten point checklist.
authors.affiliation: Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Huf
authors.forename: Klaudius
authors.initials: K
authors.lastname: Kalcher
authors.forename: Gerald
authors.initials: G
authors.lastname: Pail
authors.forename: Michaela-Elena
authors.initials: ME
authors.lastname: Friedrich
authors.forename: Peter
authors.initials: P
authors.lastname: Filzmoser
authors.forename: Siegfried
authors.initials: S
authors.lastname: Kasper
mesh_terms: D000928:Antidepressive Agents / Q000627:therapeutic use; D003625:Data Collection; D003627:Data Interpretation, Statistical; D003866:Depressive Disorder / Q000188:drug therapy; D006801:Humans; D015201:Meta-Analysis as Topic; D015233:Models, Statistical; D017594:Publication Bias; D012107:Research Design; D015871:Scientific Misconduct
chemical_list: D000928:Antidepressive Agents